Background: Previous studies have shown that the long-term clinical outcome does not correlate with the radiographic outcome in patients treated with Harrington instrumentation for adolescent idiopathic scoliosis. Cotrel-Dubousset instrumentation has been reported to provide better correction radiographically, but it is unclear whether it provides better long-term clinical or functional outcomes. We are not aware of any long-term studies comparing Harrington and Cotrel-Dubousset instrumentation.

Methods : Seventy-eight patients in whom adolescent idiopathic scoliosis was treated with Harrington instrumentation and fifty-seven in whom it was treated with Cotrel-Dubousset instrumentation participated in this study. The mean duration of follow-up was 20.8 years for the Harrington instrumentation group and 13.0 years for the Cotrel-Dubousset instrumentation group. The mean age at the time of follow-up was thirty-six years and twenty-eight years, respectively. Radiographs were made preoperatively and at the two-year and final follow-up examinations. The Scoliosis Research Society questionnaire was completed, a physical examination was performed, and spinal mobility and non-dynamometric trunk strength were measured at the final follow-up visit.

Results: The mean preoperative Cobb angle of the thoracic curves was 53° in the Harrington instrumentation group and 55° in the Cotrel-Dubousset instrumentation group. The mean numbers of vertebrae included in the instrumentation were 10.7 and 9.9, respectively. At the two-year follow-up evaluation, the mean postoperative Cobb angles were 38° and 25°, respectively (p < 0.0001). At the final follow-up evaluation, the mean angles were 45° and 32° (p < 0.0001). No significant difference in thoracic kyphosis or lumbar lordosis was observed between the study groups at the final follow-up evaluation. The average score on the Scoliosis Research Society questionnaire was 97 points in both groups. Measurements of non-dynamometric trunk strength corresponded with age and sex-adjusted reference values, on the average, but patients with Cotrel-Dubousset instrumentation performed significantly better in the squatting test (p = 0.010). Abnormal lumbar extension and trunk side-bending were significantly more common in the Harrington instrumentation group (p = 0.050 and p = 0.0061, respectively). Complications were recorded for nine (12%) of the patients treated with Harrington instrumentation and fifteen (26%) of those treated with Cotrel-Dubousset instrumentation (p = 0.027).

Conclusions: Cotrel-Dubousset instrumentation yielded better long-term functional and radiographic outcomes in patients with adolescent idiopathic scoliosis than did Harrington instrumentation. However, complications were more common in the Cotrel-Dubousset instrumentation group.

Level of Evidence: Therapeutic study, Level III-2 (retrospective cohort study). See Instructions to Authors for a complete description of levels of evidence.

Harrington and Cotrel-Dubousset instrumentation in adolescent idiopathic scoliosis. Long-term functional and radiographic outcomes.

Study Design. A retrospective follow-up study of adolescent idiopathic scoliosis after Harrington instrumentation and spondylodesis was conducted.Objective. To correlate radiographic parameters with the Scoliosis Research Society questionnaire in terms of patient outcome, clinical findings, spine mo

Comparison of long-term functional and radiologic outcomes after Harrington instrumentation and spondylodesis in adolescent idiopathic scoliosis: a review of 78 patients.

Correction of adolescent idiopathic scoliosis (AIS) has been reported with various systems. All-screw constructs are currently the most popular, but they have been associated with a significant decrease in thoracic kyphosis, with a potential risk of junctional kyphosis, not observed with hybrid constructs in the literature. In addition, it is important to weigh potential advantages of pedicle screw fixation against risks specific to its use. Because hybrid constructs are associated with a lower risk of complications and better sagittal correction than all-screw constructs, at present we use lumbar pedicle screws combined with a new sublaminar connection to the spine (Universal Clamps) at thoracic levels. The purpose of this study was to determine the efficacy and safety of the Universal Clamp (UC) posteromedial translation technique for correction of AIS. Seventy-five consecutive patients underwent posterior spinal fusion and hybrid instrumentation for progressive AIS. Correction was performed at the thoracic level using posteromedial translation. At the lumbar level, correction was performed using in situ contouring and compression/distractions maneuvers. A minimum 2-year follow-up was required. Medical data and radiographs were prospectively analyzed and compared using a paired t test. The average age at surgery was 15 years and 4 months (±19 months). The average number of levels fused was 12 ± 1.6. The mean follow-up was 30 ± 5 months. The average preoperative Cobb angle of the major curve was 60° ± 20°. The immediate postoperative major curve correction averaged 66 ± 13%. The average loss of correction of the major curve between the early postoperative assessment and latest follow-up was 3.5° ± 1.4°. The mean Cincinnati correction index was 1.7 ± 0.8 postoperatively, and 1.57 ± 1 at last follow up. The mean rotation of the apical vertebra was corrected from 23.3° ± 9° preoperatively to 7.3° ± 5° at last follow up (69% improvement, P < 0.0001). In the sagittal plane, the mean thoracic kyphosis improved from 23.8° ± 14.2° preoperatively to 32.3° ± 7.3° at last follow up. For the 68 patients who had a normokyphotic or a hypokyphotic sagittal modifier, thoracic kyphosis increased from 20.5° ± 9.9° to 31.8° ± 7.4°, corresponding to a mean kyphosis correction of 55% at last follow up. No intraoperative complication occurred and none of the patients developed proximal junctional kyphosis during the follow up. The principal limitation of the UC technique was the rate of proximal posterior prominence (14.6%), leading us to recommend the use of conventional claws at the upper extremity of the construct. The technique was safe, and reduced operative time, radiation exposure, and blood loss. While achieving correction of deformity in the coronal and axial planes equivalent to the best reported results of all-screw or previous hybrid constructs, the UC hybrid technique appears to provide superior correction in the sagittal plane. The excellent outcome in all three planes was maintained at 2 year follow up.

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Efficacy and safety of posteromedial translation for correction of thoracic curves in adolescent idiopathic scoliosis using a new connection to the spine: the Universal Clamp

Study design A retrospective comparison of the clinical, radiologic, and functional results of Cotrell-Dubousset (CD) and Universal Spine System (USS) instrumentation for adolescent idiopathic scoliosis (AIS). Objectives To establish whether there are any differences in outcome between the 2 instrumentation systems. Summary of background data CD is the first complex posterior double rod instrumentation system to provide multiple hook fixation. USS instrumentation permits the use of rod translation instead of rod rotation, the option to secure pedicle hooks with fixation screws, and the option to use transpedicular screws in the lower thoracic and lumbar spine. Midterm and long-term results of USS instrumentation are lacking. Methods Fifty-seven (mean age, 28 years at follow up) patients treated with CD instrumentation and 55 (mean age, 23 years at follow up) patients treated with USS instrumentation for AIS participated in the study. The average follow-up rate was 80% and time 13.0 years for the CD group, and 95% and 7.8 years for the USS group. Radiographs were obtained before surgery, at 2-year follow up, and at final follow up. Additionally, a physical examination was performed by 2 independent observers, and the Scoliosis Research Society (SRS) questionnaire was completed; spinal mobility and nondynamometric trunk strength were measured at the final follow-up visit. RESULTS.: The mean Cobb angle of the instrumented thoracic curve was before surgery 55 degrees (range, 36-83 degrees for the CD and 52 degrees (range, 35-85 degrees) for the USS group. The mean number of instrumented vertebrae was 9.9 (range, 7-12) in the CD and 9.8 (range, 6-12) in the USS group. At final follow up, the mean angles were 32 degrees (range, 13-63 degrees) for the CD group and 29 degrees (range, 9-63 degrees) for the USS group (not significant). No significant difference was observed in thoracic kyphosis or lumbar lordosis between the study groups at final follow up. In the SRS questionnaire, the total score averaged 97 for the CD and 101 for the USS groups, respectively. In the questionnaire, 6 (11%) patients in the CD group, but none in the USS group, reported having low back pain often or very often at rest. No correlation was found between the Cobb angle of the thoracic or lumbar curves at follow up and the total score or back pain indexes of this questionnaire. Nondynamometric trunk strength measurements corresponded with age- and sex-adjusted reference values, on average, but patients in the CD group performed significantly better in the squatting test (P = 0.021) and patients in the USS group performed better in trunk side bending (P = 0.004). Complications were recorded in 15 (26%) patients in the CD and in 13 (24%) patients in the USS group (not significant). Conclusions The midterm radiologic and functional outcomes were quite similar in both groups as were the SRS scores. The patients performed, on average, as well as did the reference population in nondynamometric trunk strength measurements. Intraoperative and late complications were similar in both groups.

Cotrel-Dubousset (CD) or Universal Spine System (USS) instrumentation in adolescent idiopathic scoliosis (AIS): comparison of midterm clinical, functional, and radiologic outcomes.

Surgical intervention for adolescent idiopathic scoliosis (AIS) should be proven to alter the natural history without introducing iatrogenic complications. The risks of surgery should be substantiated by a body of scientific research, which should show a clear superiority of surgery over observation, both in the short term and the long term. The purpose of this review was to conduct a systematic search of the literature to critically evaluate the scientific evidence on the long-term outcomes and complications of surgical intervention for AIS. Our search identified 39 distinct patient populations with a minimum average follow-up of 5 years. No long-term, prospective controlled studies exist to support the hypothesis that surgical intervention for AIS is superior to natural history. Although surgery reliably arrests the progression of deformity, achieves permanent correction, and improves appearance, there is no medical necessity for surgery based on the current body of literature. However, the surgeon must not underestimate the psychological indication that occurs when a patient is no longer able to cope with the deformity.

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Adolescent idiopathic scoliosis: 5-year to 20-year evidence-based surgical results.

The long-term effect of Harrington instrumentation was investigated using posteroanterior radiographs and computed tomographic measurements preoperatively, postoperatively, and at a mean follow-up at 10.8 years in 33 patients with idiopathic scoliosis. No patient was lost from long-term follow-up. At follow-up, the mean Cobb angle was improved by 23.7 (40%) compared with the preoperative findings. The rotation of the apical vertebra was increased significantly. The rib hump, the translation of the apical vertebra, and the sagittal diameter of the thoracic cage were unchanged. At follow-up, the mean thoracic kyphosis was 17.3, and lumbar lordosis was 22.0. This study demonstrated that the long-term effect of Harrington instrumentation was limited to an improved Cobb angle; no correction of the rotational or sagittal deformities were achieved.

L Westman

Papers

Long-term results of Harrington instrumentation in idiopathic scoliosis.